Which event provides evidence that matter can reflect waves?
A. A clear glass window allows people to see what is happening on the other side.
B. White light forms a spectrum when it passes through a prism.
C. Sound waves echo off the smooth walls of a large auditorium.
D. Earbuds transmit sound waves directly into the ear.

C. Sound waves echo off the smooth walls of a large auditorium.

Explanation:

Echo provides an evidence out of many that matter can reflect waves.

Echo is produced when sound waves bounds off the surface of a resistant  body that does not allow it to transmit.

Reflection occurs when waves changes direction when they come in contact with another body. Auditoriums are made sound proof to curtail the effect of sound waves echoing.

It is a clear proof that matter can reflect waves.

what's the question ?

b.have there own function.